BP may make first attempt to seal Gulf oil well Sunday or Monday

BP could begin pumping mud into a broken well gushing oil into the Gulf of Mexico off the Louisiana coast late Sunday or Monday, company Chief Operating Officer Doug Suttles said Wednesday. The "kill mud" would stop the flow of oil from the well before it is permanently shut with cement.

The process would be BP's first attempt at permanently closing the well.

But Suttles said the company has not yet committed to using the procedure and is still testing it. The company is measuring the oil's pressure to ensure that the mud can be pumped in at a high enough speed to overcome the oil without causing additional leaks.

BP is working to contain two oil leaks on a pipe attached to the sunken Deepwater Horizon rig. The rig, which BP leased from Transocean, exploded about 50 miles off the Louisiana coast on April 20 and subsequently sank. Eleven people on the rig were killed.

Estimates of gushing oil debated

BP and the federal government have estimated that 5,000 barrels of oil are gushing into the Gulf each day from the leaks, though some experts estimate that five times that much could be escaping.

The process of pumping mud into the well, called a top kill, requires injecting 40 barrels a minute of kill mud -- a total of about 50,000 barrels -- into the well and then sealing it with cement. The material will be pumped at high pressure down the choke and kill lines of the blowout preventer, which failed to seal the well after the rig exploded, to push the oil back into the reservoir. Choke and kill lines are used to control the amount and pressure of drilling mud in the wellbore so that surges of oil and natural gas can be kept under control.

Should the top-kill method fail, BP is considering other methods of stopping or containing the flow until the permanent stopper, a relief well, is completed in August, Suttles said.

'We're very encouraged'

So far, BP's only successful subsea effort to manage the gusher has been to begin to contain the flow.

A tube inserted into the broken pipe leaking oil into the Gulf of Mexico is collecting about 3,000 barrels of oil and 14,000 cubic feet of natural gas per day, Suttles said. The mile-long collection tube began pumping oil to a waiting ship on Sunday. It initially collected about 1,000 barrels per day, but BP has ramped up the effort in recent days.

"It's performing well," Suttles said. "We're very encouraged."

Officials also addressed concerns that the oil is heading for a powerful current that could take it to Florida.

Charlie Henry, a scientist with the National Oceanic and Atmospheric Administration, said a light sheen is nearing what is called the Loop Current but was 10 days away from reaching it. Henry said he expects the oil to degrade or dissipate before reaching Florida.

"The bulk of the oil is still way away to the northwest of the Loop Current," Henry said

Henry said the Loop Current's pattern, like that of the oil, is not constant, so NOAA is monitoring it every day. Henry said he does not believe that large pockets of oil beneath the surface are threatening to enter the Loop Current, either.